1. Field of the Invention
The present invention relates generally to devices for efficiently stripping pliable substances from a flexible, collapsible tube and, more particularly, to a simple and inexpensive device for completely removing such substances from a plastic tube having an opening from which the substance contained in the tube is extruded, such as, for example, a toothpaste tube.
2. Description of the Prior Art
One of the most efficient containers for pliable substances having a paste-like texture is a flexible tube which is collapsed as the substance contained in the tube is removed by exertion of pressure on the tube, typically by manually squeezing the tube to expel the substance, which is generally extruded through an opening substantially smaller than the diameter of the tube. Such tubes have been used for storage, transport, and sale of such diverse substances as toothpaste, hair cream, skin conditioners, greases, oil paints, and adhesives, to mention a few.
Until a number of years ago, the construction material of such collapsible tubes comprised flexible metal foils such as lead or aluminum. Metal tubes have a number of disadvantages, such as sharp edges when the tubes were bent and their propensity to tear, in addition to the unsuitability of lead for tubes containing substances for oral consumption such as toothpaste due to the toxicity of lead. The desire to allay these disadvantages led to the substitution of other materials for tube fabrication.
Within the last 20 years or so plastic tubes have largely supplanted metal foil tubes due to the factors mentioned above as well as an even more important factor, namely that of cost. Plastic tubes are easier and cheaper to construct than metal foil tubes, and present none of the disadvantages of metal foil tubes mentioned above. Plastic tubes also present neater packaging for products and are more desirable to consumers for anything from toothpaste to grease.
The frugal nature of many consumers has led to demand for devices for squeezing out the last bit of substance contained in the tube, with such devices ranging from the simple (and cheap) to the relatively complex (and more costly). Such devices may be categorized in one of two categories, namely the tube key and the dispenser.
The tube key has been the most popular device due to both its efficient operation with metal tubes and its low cost. The tube key is typically made of plastic and resembles a key with a slotted cylinder instead of the key element. The end of a tube is inserted into the slot, and the tube key is turned to wind the collapsible tube around the cylinder, squeezing the substance contained in the metal foil tube toward the end of the tube containing the opening.
The tube key works extremely well with a metal foil tube, and has been very favorably received by the public as a result. However, the tube key is much less effective with a plastic tube. Such plastic is a resilient material, the collapsed portion of a plastic tube will not wrap easily around the tube key or stay wrapped once it is around the tube key.
The practical effect of this is that the plastic tube must be rewound with each use, since after it is released it will return to its original shape. The use of the tube key with a plastic tube requires more work than it is worth and, since plastic tubes have largely replaced metal foil tubes, tube keys are no longer widely used, since they are simply not practical for use with a plastic tube.
The other type of device used to remove a substance from a tube is the dispenser, which works better with plastic tubes than does the tube key. Dispensers designed for use with disposable tubes generally hold the tube and apply pressure to the tube to cause the substance contained therein to be forced out, with some dispensers also containing valving mechanisms to meter the substance as it is extruded from the tube.
Dispensers use a number of different techniques to apply pressure to the tube, including rollers, ratchets, plungers, levers, wedges, and compressing surfaces, all with the object of economically removing all of the substance contained in the tube, with varying degrees of success. Although such devices work with plastic tubes, they have several problems making them something less than perfect solutions. One such problem is the amount of work needed is not appreciably lessened, since the tube must be installed and the device must be operated, an often complicated and time-consuming process.
Another problem is that the dispensing devices are usually eyesores, often requiring permanent installation, an unpopular requirement particularly in the bathroom when used to dispense toothpaste. Even if the device can be put away, it is generally substantially bulkier than the tube alone. Such devices also often dispense considerably more of the substance in the tube than is needed, making the devices wasteful rather than saving as intended. Finally, dispensing devices are not cheap, making the user spend a lot to save a little. Needless to say, dispensing devices are largely seen as gadgets rather than as genuine solutions to the need.
It is therefore apparent that there exists a need for an inexpensive but effective device to extrude the contents from a collapsible plastic tube. Such a device should be simple both in design and in use, making it both easily affordable and desirable to have. It should be small in size, such as the tube key for use with metal foil tubes. Finally, the device should present these advantages in a package which is commercially marketable, making it susceptible not only to mass production but also to mass sale as a desirable, affordable, and easily usable product appealing to virtually everyone.